The present invention relates to wall-marking devices which facilitate the installation of pictures, mirrors, and other wall-mounted articles, particularly where such articles are supported from behind by a catch such as a wire or cord.
An example of one such device is described in Pfeiffer, U.S. Pat. No. 3,516,165. The device comprises, essentially, an elongate ruler including, at its lower end, a hook, from which the picture can be carried. Directly opposite the lowermost portion of the hook is a sharpened point which can be used to make an impression in the wall. Holding the ruler by its upper end, the user moves the picture along the wall until the desired location is reached, whereupon the upper portion of the picture is pressed against the device causing the point to leave a mark on the wall. The mark indicates where to install the picture-hanging element (e.g. a nail or hanger) so that it will hang the picture generally in the desired location. Because of the direct alignment of the hook on one side of the device and the sharpened point on the other, it is possible to obtain relatively accurate positioning of the mark along the vertical direction without the need for guessing, for example, where behind the picture the ends of the picture wire are attached and what amount of vertical offset is needed between these ends and the picture-hanging element to account for the slack in the picture wire.
Along the horizontal direction, however, often the mark does not serve as an accurate indicator of the proper location for the picture hanging element. With the device held straight ahead of the user, for example, it is difficult to detect if the rear side of the ruler is substantially coplanar with the wall. If it isn't, this places the tip of the point in horizontal offset from the base of the point thereby shifting the mark too far off to one side. Alternatively, in selecting the desired location, often the user will move the picture to various trial positions along the wall, each time shifting the picture to one side of his or her body so that an assistant, situated further from the wall, can evaluate the full appearance of the picture at the trial position. When shifting the picture in this manner, however, there is a natural tendency to turn the wrist slightly, which, in turn, tends to cause the sharpened point of the device to turn in a horizontal plane to a new angle no longer directed straight away from the wall. As a result, if the picture is shifted to the right, for example, before marking occurs, the mark tends to be made too far to the right of its proper location, while the converse is true if the picture is first shifted to the left.
In addition to questionable accuracy, there are other problems associated with the Pfeiffer device as well. For example, in order to hold the ruler up close to the wall where the sharpened point can leave its mark, it is necessary to hold the ruler by the fingertips along its thinnest edges. This method of grasping sometimes proves insufficient, particularly when a mirror of larger size is being carried, and too often the ruler will slip from the user's grasp and fall, together with the mirror, to the floor below. Another problem is the excessive length of the device which makes it inconvenient to carry the device about on one's person. Finally, when retrieving the device from storage, too often the user will be stabbed by the sharpened point, particularly where it is necessary to pick the device out from a disorganized clutter of tools. Although Pfeiffer describes a removable cap for shielding the point, this small item is easily misplaced or lost, often making it necessary to store the tool without the desired safeguard.
A somewhat different but related wall-marking device is described in Bendick, U.S. Pat. No. 4,382,337. Like the Pfeiffer device, the Bendick device, at least in one of its embodiments, includes a sharpened point, but here the point projects from a disc-like plate which is suspended from the lower end of a rope. The picture wire is received inside a groove formed along the thick base of the point where it emerges outwardly from the disc.
Although the rope type grip makes the Bendick device easy to collapse and carry, it also requires that the user push on the center of the picture to force the point against the wall. Concern about damage to the picture or breakage of the glass sometimes covering the picture often prevents the user from applying sufficient force to make a noticeable mark on the wall. Moreover, because of the natural tendency of the rope to twist, even when held directly in front of the user, the point will frequently turn within a horizontal plane to an undetected new position at an angle with the wall. Accordingly, the accuracy of the Bendick device is no more reliable than that of the Pfeiffer device. Nor is the rope of sufficient thickness to provide a firm grip, and the device can easily slip from the user's hand when heavily weighted down, such as by a large mirror.
In Greene and Babitz, U.S. Pat. Nos. 4,455,756 and 4,637,583, respectively, an alternative type of picture installing device is described of a fundamentally different character from the type shown in Pfeiffer and Bendick. This alternative type of device does not include a wall-marking element and, therefore, is not a wall-marking device as such. Instead, the hanger that ultimately will attach the picture to the wall is made a detachable part of the device, so that after the picture is lifted with the device by the hanger, and after the device is laid flat against the wall with the picture in its desired position, adhesive on the back of the hanger, coming in contact with the wall, holds the hanger fast to the wall, whereupon the remainder of the device can be uncoupled from the hanger for reuse. In Greene, the hanger is uncoupled from a reusable lower handle by rupturing the adhesive which holds the hanger to the handle. In Babitz, the hanger is uncoupled from a reusable upper strap by swiveling a loop carried at the lower end of the strap out from under a folded-over portion of the hanger.
Although the specific problem of horizontal misalignment of the wall-marking element does not exist in this alternative type of device, the more general problem of inaccuracy in the positioning of the hanger still remains. In particular, while the picture is being shifted to its desired position, but before the picture has exactly reached the desired position, often the exposed adhesive on the rear side of the hanger will bond prematurely to the wall. While it is sometimes possible to remove and relocate the hanger, this cannot be done without a significant risk of causing damage to the surface finish of the wall. Moreover, after being installed for some time, if it becomes necessary to move a picture to a new position, the risk of damage to the wall from removal of the hanger becomes even greater. Another significant limitation of this alternative type of device is the need to replace the hanger, after each installation, with a new hanger, where this new hanger is specially adapted for releasable coupling to the reusable portion of the device, thereby increasing the expense of the device with each installation.
Accordingly, it is an object of the present invention to provide a wall-marking device that, in accordance with the desired position of a picture on the wall, marks, with improved accuracy, the corresponding location on the wall at which to install the picture-hanging element.
A related object of present invention is to provide such a device which will remain accurate even when the user of the device shifts the picture to one side of himself or herself before marking the desired position.
Another object of the present invention is to provide a wall-marking device which, throughout its use, can be gripped securely by the entire hand without exhibiting a tendency to slip or pull away from the hand.
A further object of the present invention is to provide a wall-making device offering both sufficient leverage to leave a conspicuous mark and sufficient compactness to store in a pocket.
Yet another object of the present invention is to provide a wall-marking device of the type employing a sharp point for the wall-marking element in which protection against stabbing injuries is offered without the need for removable and easily lost caps.